estep: Expectation step for Expectation-Maximisation algorithm
In markajoc/MBCbigP: Model-Based Clustering for High-Dimensional Data

Expectation step for Expectation-Maximisation algorithm

estep(x, pro, mean, sigma, groups)

estep_cond(x_A, x_B, pro, mean_A, mean_B, sigma_AA, sigma_AB, sigma_BB, groups)

estep_cond2(x_A, x_B, pro, mean_A, mean_B, sigma_AA, sigma_AB, sigma_BB, groups,
  oldz = NULL)

`x, x_A, x_B`	A matrix of data.
`pro`	A vector of mixing proportions.
`mean, mean_A, mean_B`	A 2-D array of mean vectors.
`sigma, sigma_AA, sigma_AB, sigma_BB`	A 3-D array of covariance matrices.
`groups`	The integer number of groups.
`oldz`	Previous matrix of cluster probabilities.